3.4.2. Carbon dioxide and oxygen concentrations
The concentrations of carbon dioxide and oxygen are reported in
Tables 4 and 5, respectively. The concentration of carbon dioxide in
the clamshell increased with increased storage time. On Day10, the
concentrations of carbon dioxide in L-high, RT-low and RT-high
were significantly greater than the concentration of carbon dioxide in control, while the concentration of oxygen in these treatments were significantly lower than the concentration of oxygen in
control (p 0.05). The production of CO2 is correlated with the
depletion of O2 (Nielsen & Leufven, 2008). Thus, it can be concluded
that EOs in the packaging system rendered higher fruit respiration
rate. Perdones, Sanchez-Gonzalea, Chiralt, and Vargas (2012) also
reported that strawberry coated with chitosan-lemon oil had
higher oxygen consumption during storage than those coated with
chitosan alone. They explained that EO in the coating affects the
metabolic pattern of strawberry and modifies the respiration
behaviour, which is possibly happened in our current study as well.
Additionally, on visual observation, on Day8 and Day10, skin
burning was found on strawberry packed in C-high treatment. The
chitosan beads had absorbed water and swollen until they reached
saturation point, at which they could not absorb more water. Some
water that was absorbed in the beads might dissolve lactic acid
retained in the beads. When acidic water is deposited on fruit skin,
it caused skin burning, which might affect the respiration rate.
However, there was no occurrence of burn observed in the chitosan
beads containing the EOs.